Deployment constraining sheath that enables staged deployment by device section

ABSTRACT

Various aspects of the present disclosure are directed toward medical devices, systems, and methods. The medical devices may include a portion having a radially expansive force greater than a radially expansive force other portions of the device. In addition, the medical device may include one or more constraining mechanisms for deployment of the medical devices.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. Application No. 15/955,381, filed Apr. 17, 2018, which claims the benefit of Provisional Application No. 62/486,744, filed Apr. 18, 2017, which are incorporated herein by reference in their entireties for all purposes.

TECHNICAL FIELD

This disclosure relates generally to medical devices, and more specifically, to medical devices for connecting tissue layers to create an anastomosis, implantable devices for occluding inhibiting or preventing material movement through tissue apertures, sealing, and allowing healing of defects in tissues, and deployment of the medical devices discussed herein.

BACKGROUND

An anastomosis is a cross-connection between two tissue structures, such as blood vessels or intestines. For example, in the context of coronary artery bypass graft surgery, a graft vessel is anastomosed to a native coronary artery so that blood can flow through the graft vessel.

Anastomoses can be created in various manners including, but not limited to: end-to-end, end-to-side, and side-to-side anastomoses. Often, suturing is used to create such anastomoses.

SUMMARY

Various aspects of the present disclosure are directed toward medical device systems. The medical device systems may include an expandable medical device having a first end portion, a second end portion, and an intermediate portion between the first end portion and the second end portion. The intermediate portion of the expandable medical device may include a radially expansive force greater than a radially expansive force of at least one of the first end portion and the second end portion. In addition, the expandable medical device may include a first constraining mechanism configured to releasably constrain the expandable medical device, and a second constraining mechanism arranged between the expandable medical device and the first constraining mechanism and configured to lessen expansion of the intermediate portion of the expandable medical device in response to release of the first constraining mechanism.

Various aspects of the present disclosure are also directed toward systems for deploying a medical device having a first flange, a second flange, and an intermediate portion therebetween and a delivery configuration and a deployed configuration. The systems include a first constraining mechanism configured to constrain the expandable medical device to the delivery configuration and deploy the first flange and the second flange to the deployed configuration in response to release thereof, and a second constraining mechanism arranged between the expandable medical device and the first constraining mechanism and configured to maintain the intermediate portion of the expandable medical device in an intermediate configuration in response to release of the first constraining mechanism.

Aspects of the disclosure are also directed toward methods of deploying an expandable medical device having a delivery configuration and a deployed configuration. The methods include positioning the expandable medical device at the target location (with expandable medical device including a first end portion, a second end portion, and an intermediate portion having a radially expansive force greater than a radially expansive force of the first end portion). The methods also include releasing a first constraining mechanism to deploy the first end portion and the second end portion to the deployed configuration and deploy the intermediate portion to an intermediate configuration. Further, the methods include releasing a second constraining mechanism to deploy the intermediate portion to the deployed configuration.

According to one example (“Example 1”), a medical device system includes an expandable medical device including a first end portion, a second end portion, and an intermediate portion therebetween, the intermediate portion having a radially expansive force greater than a radially expansive force of at least one of the first end portion and the second end portion; a first constraining mechanism configured to releasably constrain the expandable medical device; and a second constraining mechanism arranged between the expandable medical device and the first constraining mechanism and configured to lessen expansion of the intermediate portion of the expandable medical device in response to release of the first constraining mechanism.

According to another example (“Example 2”) further to Example 1, the first constraining mechanism and the second constraining mechanism are configured to deploy the intermediate portion of the expandable medical device to an intermediate configuration and deploy the first end portion and the second end portion of the expandable medical device to a deployed configuration in response to release of the first constraining mechanism.

According to another example (“Example 3”) further to Example 2, the second constraining mechanism is configured to release and deploy the intermediate portion of the expandable medical device to the deployed configuration.

According to another example (“Example 4”) further to Example 3, the second constraining mechanism is configured to release in response to a force applied thereto.

According to another example (“Example 5”) further to Example 4, the force is a radial force applied within the intermediate portion of the expandable medical device, and the second constraining mechanism is configured to remain coupled to the expandable medical device subsequent to the force being applied thereto.

According to another example (“Example 6”) further to Example 1, the first end portion includes a first flange, the second end portion includes a second flange, and the intermediate portion includes a substantially cylindrical shape.

According to another example (“Example 7”) further to Example 6, the expandable medical device includes a first inflection area between the first flange and the intermediate portion, a second inflection area between the second flange and the intermediate portion, and the second constraining mechanism is arranged between the first inflection area and the second inflection area.

According to another example (“Example 8”) further to Example 1, the second constraining mechanism is coupled to the expandable medical device, and the first constraining mechanism is configured to deploy the expandable medical device and uncouple from the expandable medical device in response to tension applied to the first constraining mechanism.

According to another example (“Example 9”) further to Example 1, the first constraining mechanism is configured to releasably constrain the expandable medical device to a substantially cylindrical delivery configuration.

According to another example (“Example 10”) further to Example 9, the first constraining mechanism extends from a proximal end of the expandable medical device to a distal end of the expandable medical device and back toward a proximal end of the expandable medical device.

According to one example (“Example 11”) a system for deploying a medical device having a first flange, a second flange, and an intermediate portion therebetween, a delivery configuration, and a deployed configuration. In Example 11, the system includes: a first constraining mechanism configured to constrain the medical device to the delivery configuration and deploy the first flange and the second flange to the deployed configuration in response to release of the first constraining mechanism; and a second constraining mechanism arranged between the medical device and the first constraining mechanism and configured to maintain the intermediate portion of the medical device in an intermediate configuration in response to release of the first constraining mechanism.

According to another example (“Example 12”) further to Example 11, the intermediate portion includes a radially expansive force greater than a radially expansive force of at least one of the first flange and the second flange.

According to another example (“Example 13”) further to Example 11, the second constraining mechanism is coupled to the medical device and secured to the intermediate portion.

According to another example (“Example 14”) further to Example 11, the second constraining mechanism is arranged about a circumference of the intermediate portion of the medical device.

According to another example (“Example 15”) further to Example 11, a diameter of the intermediate portion in the intermediate configuration is approximately between 40% to 80% less than a diameter of the intermediate portion in the deployed configuration.

According to another example (“Example 16”) further to Example 11, the first constraining mechanism is configured to deploy the medical device and uncouple from the medical device in response to release of the first constraining mechanism.

According to one example (“Example 17”), a method of deploying an expandable medical device having a delivery configuration and a deployed configuration. In Example 17, the method includes positioning the expandable medical device at the target location, the expandable medical device including a first end portion, a second end portion, and an intermediate portion therebetween, the intermediate portion having a radially expansive force greater than a radially expansive force of the first end portion; releasing a first constraining mechanism to deploy the first end portion and the second end portion to the deployed configuration and deploy the intermediate portion to an intermediate configuration; and releasing a second constraining mechanism to deploy the intermediate portion to the deployed configuration.

According to another example (“Example 18”) further to Example 17, releasing the second constraining mechanism includes applying a force to the second constraining mechanism to deploy the intermediate portion to the deployed configuration from the intermediate configuration.

According to another example (“Example 19”) further to Example 17, a diameter of the intermediate portion in the intermediate configuration is approximately between 40% to 80% less than a diameter of the intermediate portion in the deployed configuration.

According to another example (“Example 20”) further to Example 17, releasing the first constraining mechanism includes uncoupling the first constraining mechanism from the expandable medical device, and releasing the second constraining mechanism includes maintaining at least a portion of the second constraining mechanism attached to the intermediate portion of the expandable medical device.

According to one example (“Example 21”) a medical device system includes an expandable medical device including a first end portion, a second end portion, and an intermediate portion therebetween, the intermediate portion having a radially expansive force greater than a radially expansive force of at least one of the first end portion and the second end portion; a first constraining mechanism configured to releasably constrain the expandable medical device; and a second constraining mechanism arranged between the expandable medical device and the first constraining mechanism and configured to lessen expansion of the intermediate portion of the expandable medical device in response to release of the first constraining mechanism.

According to another example (“Example 22”) further to Example 21, the first constraining mechanism and the second constraining mechanism are configured to deploy the intermediate portion of the expandable medical device to an intermediate configuration and deploy the first end portion and the second end portion of the expandable medical device to a deployed configuration in response to release of the first constraining mechanism.

According to another example (“Example 23”) further to any one of Examples 21-22, the second constraining mechanism is configured to release and deploy the intermediate portion of the expandable medical device to the deployed configuration.

According to another example (“Example 24”) further to Example 23, the second constraining mechanism is configured to release in response to a force applied thereto.

According to another example (“Example 25”) further to Example 24, the force is a radial force applied within the intermediate portion of the expandable medical device, and the second constraining mechanism is configured to remain coupled to the expandable medical device subsequent to the force being applied thereto.

According to another example (“Example 26”) further to any one of Examples 21-25, the first end portion includes a first flange, the second end portion includes a second flange, and the intermediate portion includes a substantially cylindrical shape.

According to another example (“Example 27”) further to Example 26, the expandable medical device includes a first inflection area between the first flange and the intermediate portion, a second inflection area between the second flange and the intermediate portion, and the second constraining mechanism is arranged between the first inflection area and the second inflection area.

According to another example (“Example 28”) further to any one of Examples 21-27, the second constraining mechanism is coupled to the expandable medical device, and the first constraining mechanism is configured to deploy the expandable medical device and uncouple from the expandable medical device in response to tension applied to the first constraining mechanism.

According to another example (“Example 29”) further to any one of Examples 21-28, the first constraining mechanism is configured to releasably constrain the expandable medical device to a substantially cylindrical delivery configuration.

According to another example (“Example 30”) further to Example 29, the first constraining mechanism extends from a proximal end of the expandable medical device to a distal end of the expandable medical device and back toward a proximal end of the expandable medical device.

According to one example (“Example 31”), a system for deploying a medical device having a first flange, a second flange, and an intermediate portion therebetween, a delivery configuration, and a deployed configuration with the system including: a first constraining mechanism configured to constrain the medical device to the delivery configuration and deploy the first flange and the second flange to the deployed configuration in response to release of the first constraining mechanism; and a second constraining mechanism arranged between the medical device and the first constraining mechanism and configured to maintain the intermediate portion of the medical device in an intermediate configuration in response to release of the first constraining mechanism.

According to another example (“Example 32”) further to Example 31, the intermediate portion includes a radially expansive force greater than a radially expansive force of at least one of the first flange and the second flange.

According to another example (“Example 33”) further to any one of Examples 31-32, the second constraining mechanism is coupled to the medical device and secured to the intermediate portion.

According to another example (“Example 34”) further to any one of Examples 31-33, the second constraining mechanism is arranged about a circumference of the intermediate portion of the medical device.

According to another example (“Example 35”) further to any one of Examples 31-34, a diameter of the intermediate portion in the intermediate configuration is approximately between 40% to 80% less than a diameter of the intermediate portion in the deployed configuration.

According to another example (“Example 36”) further to any one of Examples 31-35, the first constraining mechanism is configured to deploy the medical device and uncouple from the medical device in response to release of the first constraining mechanism.

According to one example (“Example 37”), a method of deploying an expandable medical device having a delivery configuration and a deployed configuration, the method including: positioning the expandable medical device at the target location, the expandable medical device including a first end portion, a second end portion, and an intermediate portion therebetween, the intermediate portion having a radially expansive force greater than a radially expansive force of the first end portion; releasing a first constraining mechanism to deploy the first end portion and the second end portion to the deployed configuration and deploy the intermediate portion to an intermediate configuration; and releasing a second constraining mechanism to deploy the intermediate portion to the deployed configuration.

According to another example (“Example 38”) further to Example 37, releasing the second constraining mechanism includes applying a force to the second constraining mechanism to deploy the intermediate portion to the deployed configuration from the intermediate configuration.

According to another example (“Example 39”) further to any one of Examples 37-38, a diameter of the intermediate portion in the intermediate configuration is approximately between 40% to 80% less than a diameter of the intermediate portion in the deployed configuration.

According to another example (“Example 40”) further to any one of Examples 37-39, releasing the first constraining mechanism includes uncoupling the first constraining mechanism from the expandable medical device, and releasing the second constraining mechanism includes maintaining at least a portion of the second constraining mechanism attached to the intermediate portion of the expandable medical device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cutaway perspective view of an exemplary expandable medical device implanted within a patient, according to various aspects of the present disclosure.

FIG. 2 shows a delivery system for an expandable medical device, according to various aspects of the present disclosure.

FIG. 3 shows an expandable medical device in a delivery configuration, according to various aspects of the present disclosure.

FIG. 4 shows the expandable medical device, shown in FIG. 3 , in a step of a delivery, according to various aspects of the present disclosure.

FIG. 5 shows the expandable medical device, shown in FIGS. 3 and 4 , in another step of a delivery, according to various aspects of the present disclosure.

FIG. 6A shows an expandable medical device and constraining mechanism in an intermediate configuration, according to various aspects of the present disclosure.

FIG. 6B shows the expandable medical device, shown in FIG. 6A, in a fully deployed configuration, according to various aspects of the present disclosure.

DETAILED DESCRIPTION

Persons skilled in the art will readily appreciate that various aspects of the present disclosure can be realized by any number of methods and apparatus configured to perform the intended functions. It should also be noted that the accompanying figures referred to herein are not necessarily drawn to scale, but may be exaggerated to illustrate various aspects of the present disclosure, and in that regard, the figures should not be construed as limiting.

Various aspects of the present disclosure are directed to medical devices for connecting tissue layers, for example, to circumvent a conduit or organ blockage, such as by creating a direct passage between tissue structures to create an anastomosis that facilitates material flow therebetween. The expandable medical devices may be endoscopically deployable or deliverable via a catheter and may be self-expanding to facilitate a secure connection between the tissue structures. The present disclosure discusses one or more constraining mechanisms that facilitate deployment of the expandable medical devices that facilitate delivery thereof and lessen misdeployment.

FIG. 1 is a cutaway perspective view of an exemplary expandable medical device 100 implanted within a patient, according to various aspects of the present disclosure. The expandable medical device 100 is configured to be implanted in a patient to create a fluidic connection between spaces, tissue structures, conduits, organs, and the like, and combinations thereof. As shown in FIG. 1 , for example, the expandable medical device 100 may be used to connect a gallbladder 102 (that defines an internal gallbladder space 104) with an intestine 106 (that defines an internal intestinal space 108). As a result, the expandable medical device 100 acts as a fluidic shunt device between the internal gallbladder space 104 and the internal intestinal space 108.

Such an implementation may provide a beneficial treatment to the patient when, for example, a flow blockage exists in the native anatomical conduits connecting the internal gallbladder space 104 and the internal intestinal space 108. In certain instances the patient may have one or more gallstones that cause a blockage of the patient’s cystic duct 110 and/or common bile duct 112. In such a case, the expandable medical device 100 may provide a fluidic passageway such that bile from the gallbladder 102 may flow into the intestine 106.

The expandable medical device 100 may include a first end portion 114, a second end portion 116, and an intermediate portion 118 therebetween. The intermediate portion 118 defines a lumen 120 that extends longitudinally from the first end portion 114 to the second end portion 116. The lumen 120 may act as a connection (e.g., a shunt passageway) between the two spaces (e.g., tissue structures, conduits, organs) that the expandable medical device 100 connects. In the example shown in FIG. 1 , the lumen 120 acts as a connection between the internal gallbladder space 104 and the internal intestinal space 108, such that the internal gallbladder space 104 is in fluid communication with the internal intestinal space 108 via the expandable medical device 100.

Although FIG. 1 shows the expandable medical device 100 connecting the gallbladder 102 and the intestine 106 of a patient, the expandable medical device 100 may be used in conjunction with various body tissue structures and organs such as, but not limited to, stomachs, colons, small intestines, pancreases, blood vessels, bladders, kidneys, and conduits.

FIG. 2 shows a delivery system 200 for an expandable medical device, according to various aspects of the present disclosure. The delivery system 200 may include a catheter body 202 upon which the expandable medical device (not shown) may be arranged. The delivery system 200 also includes a first constraining mechanism 204 configured to constrain the expandable medical device to a delivery or constrain configuration. The first constraining mechanism 204 may be used in connection with a second constraining mechanism (as shown and discussed in further detail below with reference to FIGS. 3-6 ).

To deploy the expandable medical device arranged with the delivery system 200, tension may be applied to a deployment line 206 coupled to the first constraining mechanism 204. The deployment line 206 is accessible to a user such as a physician and may be arranged through a port 208 in the catheter body 202. In response to tension applied to the deployment line 206, the primary constraining mechanism 204 may open, withdraw or evert from an end of the delivery system 200, such as a distal tip 210, toward the port 208. In some embodiments, the first constraining mechanism 204 may have multiple layers constraining the expandable medical device and as such may move from one end of the delivery zone to the other end multiple times during deployment. In certain instances, the delivery system 200 may also include a skirt 212 that is arranged about the first constraining mechanism 204 prior to the delivery system 200 being traversed to a target location within a patient.

FIG. 3 shows an expandable medical device 300 in a delivery configuration, according to various aspects of the present disclosure. As shown in FIG. 3 , a first constraining mechanism 302 is configured to constrain the expandable medical device 300 to the delivery configuration. The first constraining mechanism 302 extends between a proximal end 306 of the expandable medical device 300 to a distal end 308 of the expandable medical device 300. In addition, the expandable medical device 300 may be arranged on a delivery catheter or delivery system 310. The delivery catheter or delivery system 310, in certain instances, is routed within a patient to a target location for delivery of the expandable medical device 300.

To deploy the expandable medical device 300, tension may be applied to a deployment line 312 coupled to the first constraining mechanism 302, which is accessible to a user such as a physician. In response, the first constraining mechanism 302 may open, withdraw or evert from the proximal end 306 towards the distal end 308 and then continue back toward the proximal end 306 of the expandable medical device 300. Releasing the first constraining mechanism 302 in this manner may deploy the distal end 308 of the expandable medical device 300 prior to deploying the remaining portions of the expandable medical device 300.

FIG. 4 shows the expandable medical device 300 after deployment of the distal end 308 of the expandable medical device 300. As shown therein, the expandable medical device 300 may include a first flange 314 arranged at the distal end 308. The first flange 314 may be deployed after the first constraining mechanism 302 is withdrawn past the first flange. The user may continue to apply tension to the deployment line 312 of the first constraining mechanism 302 to continue deployment of the expandable medical device 300.

FIG. 5 shows the expandable medical device 300 after deployment of the proximal end 306 of the expandable medical device 300. As shown therein, the expandable medical device 300 may include a second flange 316 arranged at the proximal end 306. The first constraining mechanism 302 has been released past the proximal end 306 of the expandable medical device 300, and released and uncoupled from the expandable medical device 300. Thus, the first constraining mechanism 302 is configured to release and deploy the first flange 314 and the second flange 316 to a fully-deployed configuration in response to release thereof. An intermediate portion 318 of the expandable medical device 300, however, remains in an intermediate configuration as shown in FIG. 5 .

A second constraining mechanism 304, arranged between the expandable medical device 300 and the first constraining mechanism 302 in the delivery configuration shown in FIGS. 2 and 3 , is configured to maintain the intermediate portion 318 of the expandable medical device 300 in the intermediate configuration after the release of the first constraining mechanism 302. The intermediate portion 318 of the expandable medical device 300 may have a radially expansive force greater than a radially expansive force of one or both of the first flange 314 and the second flange 316 when they are constrained by the first constraining mechanism 302. As noted with reference to FIGS. 6A and B, for example, the expandable medical device 300 may include a plurality of elongate elements. The plurality of elongate elements may have a greater density and/or winding pattern in the intermediate portion 318 of the expandable medical device 300 than in one or both of the first flange 314 and the second flange 316. In addition and as a result, the intermediate portion 318 of the expandable medical device 300 has a greater resistance to compressive force (a greater radial strength) than one or both of the first flange 314 and the second flange 316.

In certain instances, the intermediate portion 318 is approximately cylindrical whereas the first flange 314 and the second flange 316 deploy approximately perpendicular to the intermediate portion 318 such that the expandable medical device 300 includes an hourglass shape having a lumen therethrough in an intermediate configuration (shown in FIG. 5 ). The second constraining mechanism 304 is coupled to the expandable medical device 300 and is secured to the intermediate portion 318. The second constraining mechanism 304 is arranged about a circumference of the intermediate portion 318 of the expandable medical device 300.

To facilitate staged deployment of the expandable medical device 300, the second constraining mechanism 304 may be configured to mitigate against premature expansion of the intermediate portion 318. The expandable medical device 300, in certain instances, is self-expanding and therefore is biased to deploy to the full-deployed configuration from the delivery configuration. In certain instances, the intermediate portion 318 and the first flange 314 and/or the second flange 316 having different radial forces may result in forces from the intermediate portion 318, desiring to be in the deployed configuration, to force the first constraining mechanism 302 from the expandable medical device 300. The second constraining mechanism 304 is configured to lessen expansion of the intermediate portion 318 by deploying the intermediate portion 318 to the intermediate configuration as opposed to directly to the deployed configuration.

The second constraining mechanism 304 is configured to release in response to a force applied thereto. In certain instances, the force is applied from within the intermediate portion 318 of the expandable medical device 300 to break, fracture, or distend the second constraining mechanism 304. In certain instances, the second constraining mechanism 304 remains coupled to the intermediate portion 318 of the expandable medical device 300 after release thereof. The intermediate portion 318 of the expandable medical device 300 may deploy to the fully-deployed configuration, for example, as shown in FIG. 6B, after release of the second constraining mechanism 304.

FIG. 6A shows an expandable medical device 600 and constraining mechanism 602, according to various aspects of the present disclosure, in an intermediate configuration. The expandable medical device 600 may include a first end portion 604 having a flange shape, a second end portion 606 having a flange shape, and an intermediate portion 608 extending therebetween.

In addition, the first end portion 604, the second end portion 606, and the intermediate portion 608 are formed by a framework of elongate elements 610. As shown in FIG. 6A, the elongate elements 610 in the intermediate portion 608 include a greater density than the first end portion 604 and the second end portion 606. The expandable medical device 600 may include a covering material 612 (which may also be referred to herein as a “covering”). In certain instances, the covering material 612 is disposed on some or all of the first end portion 604, the second end portion 606, and the intermediate portion 608. The elongate elements 610 in the intermediate portion 608 include a greater concentration or greater windings than the first end portion 604 and the second end portion 606. Thus, the intermediate portion 608 has a greater resistance to radial forces than the first end portion 604 and the second end portion 606. In certain instances, the difference in density of the elongate elements 610 in the intermediate portion 608 and the first end portion 604 and the second end portion 606 causes the first end portion 604 and the second end portion 606 results in the intermediate portion 608 having a greater radial expansive force than the first end portion 604 and the second end portion 606.

In addition and in certain instances, the intermediate portion 608 includes a radially expansive force greater than a radially expansive force than one or both of the first end portion 604 and the second end portion 606 in the delivery (constrained) configuration. The expandable medical device 600 is deployed by releasing a first constraining mechanism (e.g., as shown in FIG. 3 ). A second constraining mechanism, such as the constraining mechanism 602 shown in FIG. 6A, may be configured to lessen expansion of the intermediate portion 608 of the expandable medical device 600 in response to release of the first constraining mechanism. In certain instances and as shown in FIG. 6A, the second constraining mechanism 602 may be arranged to extend across the intermediate portion 608 of the expandable medical device 600. In addition and as shown in FIG. 6A, the second constraining mechanism 602 is configured to deploy the intermediate portion 608 of the expandable medical device 600 to an intermediate configuration, between the delivery configuration (shown in FIGS. 2 and 3 ) and a fully-deployed configuration shown in FIG. 6B, in response to release of the first constraining mechanism.

In addition to deploying the intermediate portion 608 of the expandable medical device 600 to the intermediate configuration, the first end portion 604 and the second end portion 606 are deployed to the deployed configuration after release of the first constraining mechanism (e.g., as shown in FIGS. 3-5 ).

In the intermediate configuration, the intermediate portion 608 of the expandable medical device 600 may include a diameter less than a diameter of the intermediate portion 608 of the expandable medical device 600 in the deployed configuration. The diameter of the intermediate portion 608 in the intermediate configuration may be approximately between 40% to 80% less than a diameter of the intermediate portion 608 in the deployed configuration. The second constraining mechanism 602 may constrain the intermediate portion 608 in the intermediate configuration until the second constraining mechanism 602 is released. For example, the second constraining mechanism 602 is configured to release and deploy the intermediate portion 608 of the expandable medical device 600 to the fully deployed configuration. The second constraining mechanism 602 is released in response to a force applied thereto. In certain instances, the force may be a radial force applied within the intermediate portion 608 of the expandable medical device 600. In addition, the force may be applied by an inflatable balloon or other force applied from within the intermediate portion 608 of the expandable medical device 600.

The second constraining mechanism 602 may release, rupture, distend, or otherwise break in response to the force. Further, the second constraining mechanism 602 may be configured to remain coupled to the expandable medical device 600 subsequent to the force being applied thereto with the first constraining mechanism being configured to deploy the expandable medical device 600 and uncouple from the expandable medical device 600 in response thereto. The second constraining mechanism 602 may surround or enclose a circumference of the intermediate portion 608 of the expandable medical device 600. In addition, the second constraining mechanism 602 may be a flexible film (formed from, for example, polytetrafluoroethylene (ePTFE)) and attached (and remain attached to after release of the first constraining mechanism) to one or more portions of the intermediate portion 608 of the expandable medical device 600 via a medical adhesive (e.g., fluorinated ethylene propylene (FEP), a polymer of tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride (THV), and other biocompatible adhesives).

As noted above, the intermediate portion 608 includes a radially expansive force that is greater than a radially expansive force than one or both of the first end portion 604 and the second end portion 606 in the constrained (delivery) configuration. Thus, the second constraining mechanism 602 may be configured to mitigate against premature deployment of the expandable medical device 600. The intermediate portion 608 has a radially expansive force greater than one or both of the first end portion 604 and the second end portion 606 that may force the first constraining mechanism (not shown) to be removed/released from the expandable medical device 600 without a user applying tension to remove the first constraining mechanism. The second constraining mechanism 602 may be configured to lessen expansion of the intermediate portion 608, thereby mitigating against the potential for the intermediate portion 608 to force the first constraining mechanism from the expandable medical device 600 without the user removing the first constraining mechanism.

In addition, the second constraining mechanism 602 may be arranged between the first constraining mechanism (prior to release thereof) and the intermediate portion 608 of the expandable medical device 600. Further, the second constraining mechanism 602 may be arranged within the bounds of the intermediate portion 608 of the expandable medical device 600 as shown in FIG. 5A. The expandable medical device 600 may include a first inflection area 614 between the first end portion 604 and the intermediate portion 608, and a second inflection area 616 between the second end portion 606 and the intermediate portion 608. The first inflection area 614 and the second inflection area 616 may transition the substantially cylindrical shape of the intermediate portion 608 to, respectively, the first end portion 604 and the second end portion 606. Further, the second constraining mechanism 602 may be arranged to extend between the first inflection area 614 and the second inflection area 616. The second constraining mechanism 602 extending between but not covering the first inflection area 614 and the second inflection area 616 may facilitate deployment of the first end portion 604 and the second end portion 606 by not interfering or encroaching on the first end portion 604 and the second end portion 606 while maintaining the staged deployment of each portion of the expandable medical device 600.

In certain instances, the intermediate portion 608 of the expandable medical device 600 is constructed to have a tailored radial strength by, for example, varying sine wave amplitude, angle, number of apices per row, number of rows, and/or wire diameter of the elongate elements 610 (or other similar constructions). In addition, the intermediate portion 608 of the expandable medical device 600 includes a radial strength to resist circumferential loading from the surrounding tissue. In certain instances, the radial strength of the intermediate portion 608 of the expandable medical device 600 facilitates remodeling of the tissue external to the intermediate portion 608 to become approximate in size to the outer diameter of the intermediate portion 608. When the expandable medical device 600 (and the other expandable medical devices discussed herein) is implanted to form an anastomosis, the radial strength of the intermediate portion 608 may provide resistance to the hoop force applied by the surrounding tissue. Thus, the expandable medical device 600 substantially maintains an open lumen at a desired dimension.

FIG. 6B shows the expandable medical device 600, shown in FIG. 6A, in a full deployed configuration, according to various aspects of the present disclosure. The intermediate portion 608 of the expandable medical device 600 is no longer constrained by the second constraining mechanism 602. Thus, the intermediate portion 608 is in the fully-deployed configuration. As shown in comparing FIG. 6A and FIG. 6B, the intermediate portion 608 expands to a greater diameter from the intermediate configuration. The second constraining mechanism 602, in certain instances, remains coupled to the intermediate portion 608 of the expandable medical device 600 after release of the constraining force.

The expandable medical devices, as discussed herein, may form a connection between two areas. The connection may also be referred to herein as a “shunt,” “passageway,” “shunt passageway,” or “tunnel”. In certain instances, the expandable medical devices discussed herein are configured to be removable after implantation. For example, the expandable medical devices may be implanted and remain in place until the gallbladder and/or its associated ducts are cleared of blockages, after which the device is removed. In another example, the expandable medical devices may remain implanted until the body grows a tissue-anastomosis around the device, and then the device is removed. In other instances, tissue ingrowth into and/or around the device permanently implants the expandable medical device, and the expandable medical device is not removed. The expandable medical devices discussed herein may provide an alternative treatment for patients who are not suitable candidates for other types of treatments (e.g., gallbladder removal surgery) and/or to avoid known complications of other types of treatments (e.g., external biliary drainage).

In certain instances, the elongate elements or framework of the expandable medical devices may be treated in various ways to increase the radiopacity of the expandable medical devices for enhanced radiographic visualization. In some embodiments, the expandable medical devices are at least partially a drawn-filled type of NiTi containing a different material at the core, such as a material with enhanced radiopacity. In some embodiments, the devices include a radiopaque cladding or plating on at least portions of the expandable medical devices. In certain instances, one or more radiopaque markers are attached to the expandable medical devices. In certain instances, the elongate elements and/or other portions of the expandable medical devices provided herein are also visible via ultrasound, and may include portions with enhanced echogenicity.

In addition, the covering material arranged on the expandable medical devices may be generally fluid impermeable. For example, the covering material may be made of a material that inhibits or reduces passage of blood, bile and/or other bodily fluids and materials through the covering material. In certain instances, the covering material has a material composition and configuration that inhibits or prevents tissue ingrowth and/or endothelialization or epithelialization into the covering material. In addition, the covering material may be configured to inhibit or prevent tissue ingrowth and/or endothelialization such that the expandable medical devices may be more readily removed from the patient at a future date. In certain instances, the covering material, or portions thereof, may include a microporous structure that provides a tissue ingrowth scaffold for durable sealing and/or supplemental anchoring strength of the expandable medical devices.

The covering material and the constraining mechanisms may include a fluoropolymer membrane, such as an expanded polytetrafluoroethylene (ePTFE) polymer, polyvinylidene fluoride (PVDF), or polyvinylidene acetate (PVDA). In other instances, the covering material comprises a polyester, a silicone, a urethane, biocompatible polymer(s), polyethylene terephthalate (e.g., Dacron®), bioabsorbable materials, copolymers, or combinations thereof. In addition, the covering material may include a bioabsorbable web. Expanded polytetrafluoroethylene (ePTFE) membranes prepared in accordance with the methods described in U.S. Pat. No. 7,306,729 to Bacino et al., U.S. Pat. No. 3,953,566 to Gore, U.S. Pat. No. 5,476,589 to Bacino, or U.S. Pat. No. 5,183,545 to Branca et al. may be used as the covering material herein. Additionally, expanded modified PTFE and expanded copolymers of PTFE, such as described in U.S. Pat. No. 5,708,044 to Branca; U.S. Pat. No. 6,541,589 to Baillie; U.S. Pat. No. 7,531,611 to Sabol et al.; U.S. Pat. No. 8,637,144 to Ford; and U.S. Pat. No. 9,139,669 to Xu et al. may be used herein. In other embodiments, the bioabsorbable material may also provide an anti-migration feature by promoting attachment between the expandable medical devices and tissue until the bioabsorbable material is absorbed.

The covering material (or portions thereof) may also be modified by one or more chemical or physical processes that enhance one or more properties of the coating. For example, a hydrophilic coating may be applied to the covering material to improve the wettability and echo translucency of the covering. In certain instances, the covering material, or portions thereof, may be modified with chemical moieties that facilitate one or more of endothelial cell attachment, endothelial cell migration, endothelial cell proliferation, and resistance to or promotion of thrombosis. In certain instances, the covering material, or portions thereof, may be modified to resist biofouling. In addition, the covering material, or portions thereof, may be modified with one or more covalently attached drug substances (e.g., heparin, antibiotics, and the like) or impregnated with the one or more drug substances. The drug substances can be released in situ to promote healing, reduce tissue inflammation, reduce or inhibit infections, and to promote various other therapeutic treatments and outcomes. In some embodiments, the drug substance may be, but is not limited to a corticosteroid, a human growth factor, an anti-mitotic agent, an antithrombotic agent, a stem cell material, or dexamethasone sodium phosphate. In addition, a pharmacological agent may be delivered separately from the covering material to the target site to promote tissue healing or tissue growth.

Persons skilled in the art will readily appreciate that various aspects of the present disclosure can be realized by any number of methods and apparatus configured to perform the intended functions. It should also be noted that the accompanying figures referred to herein are not necessarily drawn to scale, but may be exaggerated to illustrate various aspects of the present disclosure, and in that regard, the figures should not be construed as limiting. 

What is claimed is:
 1. A delivery system for an expandable medical device, comprising: a catheter body; an expandable medical device arranged on the catheter body, the expandable medical device including a first end portion, a second end portion, and an intermediate portion therebetween, the first end portion transitioning to the intermediate portion at a first inflection area and the second end portion transitioning to the intermediate portion at a second inflection area; a first constraining mechanism configured to constrain at least a portion of the expandable medical device in a delivery configuration; a deployment line coupled to the first constraining mechanism, the deployment line being operable to release the first constraining mechanism in response to tension applied to the deployment line; and a skirt arranged about the first constraining mechanism.
 2. The delivery system of claim 1, wherein the skirt is operable to be positioned about the first constraining mechanism when the delivery system is being advanced toward a target location within a patient.
 3. The delivery system of claim 1, further comprising a distal tip positioned at a distal end of the catheter body.
 4. The delivery system of claim 3, wherein the first constraining mechanism is operable to evert from the distal tip toward a proximal end of the catheter body.
 5. The delivery catheter of claim 4, further comprising a second constraining mechanism, wherein the second constraining mechanism is positioned about the intermediate portion of the expandable medical device.
 6. The delivery catheter of claim 5, wherein the first constraining mechanism is positioned about the first end portion, the second end portion, and the intermediate portion of the expandable medical device.
 7. The delivery system of claim 6, wherein the first constraining mechanism is operable to release and deploy the first end portion and the second end portion of the expandable medical device to a fully-deployed configuration in response to release thereof.
 8. The delivery system of claim 7, wherein the second constraining mechanism constrains the intermediate portion in an intermediate configuration after release of the first constraining mechanism and the first and second end portions of the expandable medical device is in the fully-deployed configuration.
 9. The delivery system of claim 8, wherein the second constraining mechanism is arranged between the first constraining mechanism and the expandable medical device when in the delivery configuration.
 10. The delivery system of claim 9, wherein intermediate portion of the expandable medical device exerts a radially expansive force that is greater than a radially expansive force of the first and second end portions of the expandable medical device. 